1-cyclobutylformamides and use as herbicides



UnitedStates l atent Ofiiice 3,246,975 Patented Apr. 19, 1966 l-CYCLOBUTYEFORMAMIDES AND USE AS HERBICIDES,

Thomas R. Hopkins, Overland Park, and Ralph P. Neigh- This invention relates to novel compositions and methods for controlling plant growth, and more particularly, this invention relates to compositions and methods for inhibiting plant growth employing as the active plant growth regulator, a l-cyclobutylformamide.

There are provided by this invention novel herbicidal compositions and methods for controlling plant growth by applying to the locus of the plant a l-cyclobutylformamide. The l-cyclobutylformamides of this invention are the cyclobutanecarboxamides and the l-cyclobutylthioformamides which .are represented by the formula R1(IN/ wherein R represents a cyclobutyl ring, X represents oxygen or sulfur, and R and R are selected from the group consisting of hydrogen,'alkyl, cycloalkyl, alkenyl, alkynyl, aryl, aralkyl, heterocyclic, and taken together with the nitrogen atom to which Rs and R are attached, a heterocyclic radical. Thus, the herbicidal l-cyclobutylformamides of this invention are the unsubstituted amides or amides having one or more organic substituents on the nitrogen atom. Preferably, R is hydrogen and R is a monocyclic aryl group such as phenyl and the nuclear substituted phenyl groups. i

Examples of nitrogen substituents represented by R and R in the above formula are alkyl radicals, and especially the lower alkyl radicals having one to about eight carbon atoms, straight or branched chain; cycloalkyl radicals, especially the cyclic lower alkyl radicals having about three to eight carbon atoms; alkenyl and alkynyl radicals,

and especially the lower alkenyl and alkynyl radicals having two to about eightcarbon atoms; aralkyl radicals and especially the monocyclic aralkyl radicals such as benzyl and nuclear substituted benzyls; aryl radicals, and especially the monocyclic aryl radicals such as phenyl and nuclear substituted phenyls having nuclear substituents such as halo, and especially chloro, iodo, fluoro and bromo, alkoxy and especially lower alkoxy, cyano, nitro, alkyl and especially lower alkyl, acyloxy and hydroxy; and heterocyclic radicals, especially monocyclic radicals having nitrogen, oxygen on sulfur in addition to carbon in the ring. R and R may also be taken together with the nitrogen atom to form a heterocyclic radical, such as the monocyclic radicals having nitrogen, oxygen or sulfur in addition to carbon in the ring, for example the amides formed from piperidine or morpholine.

Representative examples of radicals represented by R and R in the above formula are hydrogen, methyl, ethyl, 2-chloroethyl, Z-hydroxyethyl, propyl, isobutyl, pentyl, isooctyl, allyl, butenyl, pentenyl, butynyl, 4-ch'loro-2-butynyl, propynyl, phenyl, na-phthyl, 3-chlorophenyl, 3-iodophenyl, 3-fluorophenyl, -4-bromophenyl, 3,4-dichlorophenyl, 2,4,5- trichlorophenyl, 3-;nethylphenyl, 3,4-dibromophenyl, 2,5- difluorophenyl, A-cyanophenyl, 3,5-dinitrophenyl, ,4-hydro y henyl, 3-ehloro-4-me hyzlp yl, 4ac t xyph y 3-methoxyphenyl, 3-trifluorome.thylphenyl, cyclopropyl, cyclohexyl, cyclobutyl, 4-cyclopropylcarbonyloxyphenyl, benzyl, 3,4-dichlorobenzyl, 2-thiazolyl, Z-pyridyl, and tr-iazolyl. Compounds having a cyclic-radical in which the amide nitrogen atom is part of the ring are formed product.

reaction.

from compounds such as piperidine, morpholine and pyrrolidine.

There are also provided by this invention certain novel l-cyclobutylformamides. Especially useful are the cyclobutanecarboxamides having the formula PCH:

in which Y represents hydrogen, halo or methyl radicals, at least one of said Ys being a halo radical. The halo radical may be any halogen, such as chloro, bromo, iodo or fluoro.

The cyclobutanecarboxamides of this invention are readily prepared by reaction of cyolobutanecarboxylic acid halide, such as the acid chloride (cyclobutanecarbonyl chloride), with the appropriate amine. Preferably, the reaction is run in the presence of an inert organic solvent such as cyclohexane, toluene, dioxane, benzene, n-hexane or n-pentane. Since hydrogen halide is a by-product of the reaction, it is desirable to use a molar excess of the amine or, preferably, a tertiary amine such as triethylamine or pyridine, to react with the hydrogen halide as it is evolved, thereby improving yields and purity of the desired The reaction takes place in a relatively short time, about 0.5 to -3 hours usually being sllfiicient at about room temperature .or slightly below room temperature. A preferred reaction temperature is around 1 5 to 25 C., which is low enough to maintain good control of the In order to make full use of the reactants, it is preferred to add the cyclobutanecarboxylic acid halide to a solution of the amine and pyridine in an organic solvent, thus maintaining an excess of amine during the reaction period. When an organic solvent for the carboxamide is used, the by-product pyridine hydrohalide can be removed by filtration and the desired carboxamide isolated from the solvent by known procedures. The crude amide can be recrystallized, such as from water-alcohol mixtures, nhexane or ethyl acetate, in the case of solids and in the case liquids, can be distilled under reduced pressure.

The 1-cyclo'butylthioformamides can be prepared by sulfurization of the corresponding cyclobutanecarboxamide with phosphorus pentasulfide at an elevated temperature, such as about -ll0 C.

The following examples illustrate the preparation of representative l-cyclobutylformamides of this invention, but are not intended to limit the invention.

EXAMPLE 1.e-N-(3,-4-DICHLOROPHENYL) CYCLOBUTANECARBOXAMIDE A solution of 6.82 grams (0.042 mole) of 3,4-dichloro aniline and 3.32 grams (0.042 mole) of pyridine in 50 ml. of benzene was stirred in a flask and cooled to about 15 ,C- .91 .0n;of5 grams ..(0.042.1nole.)...of cyclobutane carboxylic acid chloride in 10 ml. of benzene was added dropwise to the stirred amine solution at about 15-20 C. The resulting mixture was then stirred for an additional .4 hours at room temperature. After standing overnight atroom temperature, "the reaction mixture was poured into} about 60 ml. of water, the benzene layer was separated; and then dried over magnesium sulfate. After removal of the magnesium sulfate by filtration, about ml. of

n-hexane was added to the dried benzene solution. The

solution was chilled, and the crystallized product was removed by fil'tration togive 9.2 grams of N-(3,4-dichlorophenyl)cyclobutanecarboxamide, M.P. 100-102" C. Re-

' eral procedure of Example 1.

3 EXAMPLE 2 N-(3-chlorophenyl)cyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylic acid chloride with 3-chloroaniline. The purified product melted at 9899 C.

EXAMPLE 3 N-(4-nitrophenyl)cyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylic acid chloride with p-nitroaniline. The purified product melts at 124-125 C.

EXAMPLE 4 N-cyclohexylcyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylic acid chloride with cyclohexylamine. The purified product melted at 113- 116 C.

EXAMPLE 5 N-(4 chloro 2 butynyl)cyclobutanecarboxamide was prepared by the reaction of cyclobubanecarboxylic acid chloride with 4-ch loro-2-butynyl=arnine. The purified product melted at 60-61 C.

EXAMPLE 6 N-n-hexylcyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylic acid chloride with nhexylamine. The product was distilled under reduced pressure and collected at 121-123 C./1 mm. Hg.

EXAMPLE 7 N,N-pentamethylenecyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylic acid chloride with piperidine. The product was distilled under reduced pressure and collected at 89 C./ 1 mm.

EXAMPLE 8 N,N (3-oxapentamethylene)cyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylie acid chloride with morpholine. The product was distilled under reduced pressure and collected at 96 C./ 1 mm.

EXAMPLE 9 N-phenylcyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylic acid chloride with aniline. The purified product melted at 109-110 C.

EXAMPLE 11 N-(Z-pyridyl)cyclobutanecarboxamide was prepared by 4 EXAMPLE 13 N-a-naphthylcyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylic acid chloride with a-naphthylamine. The purified product melted at 147- 147.5 C.

EXAMPLE 14 N-benzylcyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylic acid chloride with ben- Zylamine. The purified product melted at 76-77 C.

EXAMPLE 15 N-allylcyclobutanecarboxarnide was prepared by the reaction of cyclobutanecarboxylic acid chloride with allylamine. The purified product melted at 5455.5 C.

EXAMPLE l6 N-tert.-bntylcyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylic acid chloride with tert.-butylamine. The purified product melted at 124- 125 C.

As hereinbefore stated, the l-cyclobutlylformamides of this invention exhibit excellent plant growth regulatory properties when applied to the locus of plants, such as the foliage of the growing plant or the plant growth medium, as for example soil in which the plant is growing or is to be grown.

The following example shows the activity of representative compounds of this invention as post-emergence herbi cides at a 5 pounds per acre rate of applicatinr Example A A water suspension of the chemical was prepared by combining 0.4 gram of the chemical to be tested with 4 ml. of a solvent mixture (3 parts Emulphor EL-719 corn= bined with one part xylene and one part kerosene) and then adding sufficient-warm water to make 40 ml. of mix= ture. Emulphor EL-719 is described as a polyoxyethyl ated vegetable oil.

Oats, wheat, peas, radish, flax, alfalfa, tomatoes, millet and sugar beets were planted in 4" pots in the greenhouse. Ten to eighteen days after the emergence of the plants, they were sprayed with the above prepared water emulsions at a rate of 5 pounds of the active chemical per acre and a spray volume of gallons per acre. Seven days after application, the plants were observed and the results of treatment recorded as in Table A.

The plants were rated as follows:

C=chlorosis N=necrosis G: growth inhibition Kznon-emergence the reaction of cyclobutanecarboxylic acid chloride with 0=no effect plants TABLE A Compound 0 ats Wheat Peas Radish Flax Millet Alfalfa Tomato 3ugar eets N-phenylcyclobutanecarboxamide N2 0 N2 N2 N3 N1 N3 N1 N-(3-chlorophenyl) cyclobutanecarboxamide N 1 N1 G1 03 N3 N 2 4 N3 0 1N1 N3 N-(3,4-dichlorophenyl) cyclobutanecarboxamide. N2 G1 N 2G3 C3N2 N3 N3 4 4 C1N2 4 N- (4-mitrophenyl) eyclobutanecarboxamide N1 0 0 N2 N2 N 1 N1 N 2 N2 N -cyclohexyl cyclobutanecarboxannde N1 0 N 1 N2 N2 N1 N2 N2 N2 N-(4-chl0r0-2-butyny1) cyclobutaneearboxamide N1 N2 N 2 N1 N2 N2 N1 N2 N 1 N-n-hexylcyclobutanecarboxamide O 0 N 1 N 1 N1 N1 0 0 N 3 N,N-pentarnethylenecyclobutanecarboxamide 0 0 0 N 1 N1 N1 0 O 0 N,N-(3-oxapenta1nethy1ene) cyelobutanecarboxamide- 0 0 0 N1 N 1 0 0 0 0 Z-aminopyridine. The product was distilled under reduced pressure and collected at 125128 C./1 mm.

EXAMPLE 12 Cyclobutanecarboxamide was prepared by the reaction of cyclobutanecarboxylic acid chloride with ammonia. The resulting product melted at 153-155 C.

Disposable paper 'halfflats Were seeded and sprayed with the acetone solutions at a rate to give lbsof the active compound per acre. One fiat, which had been seeded with alfalfa, broi'n'e', flax, oats, radishes and sugar beets, was held at 75 F. d-ay temperature; another flat which had been seeded with corn, coxcomb, cotton, crabgrass, millet and soybeans was held at 85 F. Twenty-one days after seedingand treatment the flats were examined, plant emergence and chemical effects on the seedlings were plants and soil can be achieved more readily, sash earriers may be either solids, such as talc, clay, diatom-aceous earth, sawdust, cal carbonate or the like, or liquids such its water, kerosenaaeetone, benzene, toluene, xylene, and the like, in which the active compound may be dissolved or dispersed. I

Emulsifying agents preferably are used to achieve a suitable emulsion or dispersion in liquids SilCh as water to give aqueous sprays. Emulsifyii'ig agents and wetting rated and recorded as in Table B. The rating'sy'stem was 10 agents may also be used to aid in dispersing the active the same as in Example A. compound in liquids used as the carrier in which the coin- TABLE B Compound Alfalfa Brome Flax Oats Radish Sugar Corn Cox- Cotton Crab- I Millet Soy- Beets comb grass beans N-(B-chlorophenyl)cyclobutanecarboxamide K4 0 G3 0 N4 0 G1 K4 0 0 K3 G3 N-(3,4-dich1orophenyl)cyclobutanecarboxamide K4 0 K2 0 N4 N4 0 K4 0 G2 K4 G3 N-( t-nitrophenyl)cyclobutanecarboxamide N2 N2 N1 N2 N4 N2 0 N4 K2 G2 G2 G2 N-cyclohcxyl cyclobutanecarboxamide.l. N4 N1 0 0 G2 0 0 K4 K2 0 0 G2 N-n-hex'ylcyclobutaneoarboxairiide 0 0 0 0 0 0 0 K4 0 0 0 0 N,N-(3-oxapentamcthylene)cyclobutanecarboxamide N2 N2 N2 N2 N2 N4 N2 N2 N2 N2 N2 N2 N-(2-thiazolyl)oyclobutanecarboxamide. N4 N2 G2 N1 G1 N1 0 K4 N2 G2 G2 G2 N-(Z-pyridyl)cyclobutanecarboxamide G2 N1 G2 G1 G1 0 N3 N1 G1 G3 G3 G3 Cyclobutanecarboxamide G3 0 K3 N1 0 0 0 K3 K3 0 0 K2 The N-(monocyclic aryl)cyclobutanecarboxamides are pound is not completely soluble and to increase coverage especially useful as herbicides. Examples of compounds by the active compound. Emulsifying agents and wetting in this group are the N-phenyl cyclobutanecarboxamides agents, also known as surface active agents, are sold un in which the phenyl radical is unsubstituted or has nuclear der numerous trademarks and may be either pure comsubstituents such as chloro, fluoro, bromo, cyano, lower pounds, mixtures of compounds of the same general group, alkyl, and lower alkoxy. or they maybe mixtures of compounds of different classes. The presently preferred herbicidal compounds are the There are thus also provided by this invention novel novel compounds having the formula herbicidal compositions containing one or more of the de- Y scribed l-cyclobuty-lfor-ma-mides intimately dispersed with 0 or dissolved in a surface active agent. Typical satisfacg g tory surface active agents which may be used are the alkali I metal higher alkylarylsulfonates such as sodium dodeoyl- CHZTCH benzenesulfonate and the sodium salts of alkylnaphthylwherein Y represents a hydrogen, halo or methyl radical, ene sulfonic acids, fatty alcohol sulfates such as the sodiat least one of said Ys being a halo radical. Examples urn salts of the monoesters of sulfuric acid with n-aliphatic of new compounds represented by this formula are alcohols containing about eight to eighteen carbon atoms, N (3 chl orophenyl)cyclobutanecarboxamide, long chain quaternary ammonium compounds, sodium N (4 h1 ph y1 cyclobutanecarboxamide salts of petroleum derived alkylsulfonic acids, polyethylene N-'(3-chloro-4-methylpheuyl)cyclobutanccarboxamide, sorblt'an f q alkylarylpolyf'ther ,alcohols W N (3 fluorophenyl)cyclobutamcarboxamide, soluble l gnin sulfonate salts, alkali-casein COmPOSltlOIIS, Nq(4 bmmo,phenyl)cyclobutanecarboxamide, and long chain alcohols usually conta ning about ten to eight- N43,4 dichlorophenyl)cyclobutancarboxamide een carbon atoms, and condensation products of ethylene i oxide with fatty 'HCIdS, alkylphenols and mercaptans. The Presently Preferred o p 15 Other additives such as a lanolin or kerosene emulsion, phouyl)oyolobutallooofboXamldoor Tween-20 (a product described as sorbitan monolaure- An upplloauorl Toto of about 40 P s to as 111mb ate polyoxyalkylene derivative), stickers and other auxilabollt Pound of one of more the uotlvo Compounds iary materials may be included in solid or liquid formula- P acre 18 w the o po are usod as p tions to increase coverage of the active compound. These emergence hoibloldo, an opp fate of about 5 to materials are also considered to be surface active agents. about 40 Pounds P o 18 used, Wlth about 10 to about Various changes and modifications of the invention can 20 PoundS P s If W o y are used be made and to the extent that such variations incorporate as a Post-emergence hofbloldo, an pp o rate of about the spirit of this invention they are intended to be included 0.25 to 40 pounds of one or more active compounds per withi the scope of the appended claims. acre is used, with an application rate of about 1 to 10 What is claimed is: pounds per acre being preferred. When using a water 1. The method of controlling plant growth which comemulsion of the herbicide, a spray volume of about 1 to prises applying to the locus of the plant from about 1 to about 100 gallons of q o 611111151011, and P y 10 pounds per acre of N-(4-chloro-2-butynyl)cyclobutaneabout 5 to 40 gallons, per acre is used. carboxamide in combination with a surface active agent By proper formulation and use of low application rates, d an i t di1 t the compounds of this invention can be used as selective 2. Th thod f t lli l t th hi h herbicides to kill certain species of weeds in the presence prises applying to the locus of the plant from about 1 to of other crops. 10 pounds per acre of N-(n-hexy-l)cyclobut-anecarbox- Th ex ell nt h bi id l i i of h l1-cyc1obuty.1- amide in combination with a surface active agent and an formamides of this invention requires the application of inert diluent. only small amounts of the active ingredient distributed 3. The method of controlling plant growth which comuniformly over a wide area. Of course, this is difficult to prises applying to the locus of the plant from about 1 to do employing the pure material. However, by increasing 10 pounds per acre of N-cyclohexyl cyclobutanecarboxthe bulk of this material, such as by mixing the compound amide in combination with a surface active agent and an with an inert diluent or carrier, the application to growing inert diluent.

inert diluent prior to emergence ofpl-ant growth from the 5 soil.

References Cited by the Examiner UNITED STATES PATENTS 2,441,498 5/1948 Lofgren et a1. 260'-557 YR 2,670,371 2/1954 Cusic 260557 2,677,705 5/1954 Utzin-ger 260557 2,723,192 11/1955 Todd 712.6 2,764,478 9/1956 Searle 712.6

2,866,801 12/1958 Himel et a1 260557 XR OTHER REFERENCES German Auslegeschrift, 2 pages, 1,005,784, April 4, 1957.

WALTER A. MODANCE, Primary Examiner.

10 IRVING MARCUS, DUVAL T. MCCUTCHEN,

Examiners.

ROBERT L. PRICE, NATALIE TROUSOF,

Assistant Examiners. 

1. THE METHOD OF CONTROLLING PLANT GROWTH WHICH COMPRISES APPLYING TO THE LOCUS OF THE PLANT FROM ABOUT 1 TO 10 POUNDS PER ACRE OF N-(4-CHLORO-2-BUTYNYL)CYCLOBUTANECARBOXAMIDE IN COMBINATION WITH A SURFA CE ACTIVE AGENT AND AN INERT DILUENT.
 2. THE METHOD OF CONTROLLING PLANT GROWTH WHICH COMPRISES APPLYING TO THE LOCUS OF THE PLANT FROM ABOUT 1 TO 10 POUNDS PER ACRE OF N-(N-HEXYL)CYCLOBUTANECARBOXAMIDE IN COMBINATION WITH A SURFACE ACTIVE AGENT AND AN INERT DILUENT.
 3. THE METHOD OF CONTROLLING PLANT GROWTH WHICH COMPRISES APPLYING TO THE LOCUS OF THE PLANT FROM ABOUT 1 TO 10 POUNDS PER ACRE OF N-CYCLOHEXYL CYCLOBUTANECARBOXAMIDE IN COMBINATION WITH A SURFACE ACTIVE AGENT AND AN INERT DILUENT.
 4. THE METHOD OF CONTROLLING PLANT GROWTH WHICH COMPRISES APPLYING TO THE LOCUS OF THE PLANT FROM ABOUT 10 TO 20 POUNDS PER ACRE OF N-(2-THIAZOLYL)CYCLOBUTANECARBOXAMIDE IN COMBINATION WITH A SURFACE ACTIVE AGENT AND AN INERT DILUENT PRIOR TO EMERGENCE OF PLANT GROWTH FROM THE SOIL. 